[PATCH] drm/i915/dp_mst: Work around Thunderbolt sink disconnect after SINK_COUNT_ESI read
Due to a problem in the iTBT DP-in adapter's firmware the sink on a TBT link may get disconnected inadvertently if the SINK_COUNT_ESI and the DP_LINK_SERVICE_IRQ_VECTOR_ESI0 registers are read in a single AUX transaction. Work around the issue by reading these registers in separate transactions.
The issue affects MTL+ platforms and will be fixed in the DP-in adapter firmware, however releasing that firmware fix may take some time and is not guaranteed to be available for all systems. Based on this apply the workaround on affected platforms.
See HSD #13013007775.
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13760 Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14147 Cc: stable@vger.kernel.org Signed-off-by: Imre Deak imre.deak@intel.com --- drivers/gpu/drm/i915/display/intel_dp.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 21297bc4cc00d..208a953b04a2f 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -4538,6 +4538,23 @@ intel_dp_mst_disconnect(struct intel_dp *intel_dp) static bool intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *esi) { + struct intel_display *display = to_intel_display(intel_dp); + + /* + * Display WA for HSD #13013007775: mtl/arl/lnl + * Read the sink count and link service IRQ registers in separate + * transactions to prevent disconnecting the sink on a TBT link + * inadvertently. + */ + if (IS_DISPLAY_VER(display, 14, 20) && !display->platform.battlemage) { + if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT_ESI, esi, 3) != 3) + return false; + + /* DP_SINK_COUNT_ESI + 3 == DP_LINK_SERVICE_IRQ_VECTOR_ESI0 */ + return drm_dp_dpcd_readb(&intel_dp->aux, DP_LINK_SERVICE_IRQ_VECTOR_ESI0, + &esi[3]) == 1; + } + return drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT_ESI, esi, 4) == 4; }
Due to a problem in the iTBT DP-in adapter's firmware the sink on a TBT link may get disconnected inadvertently if the SINK_COUNT_ESI and the DP_LINK_SERVICE_IRQ_VECTOR_ESI0 registers are read in a single AUX transaction. Work around the issue by reading these registers in separate transactions.
The issue affects MTL+ platforms and will be fixed in the DP-in adapter firmware, however releasing that firmware fix may take some time and is not guaranteed to be available for all systems. Based on this apply the workaround on affected platforms.
See HSD #13013007775.
v2: Cc'ing Mika Westerberg.
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13760 Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14147 Cc: Mika Westerberg mika.westerberg@linux.intel.com Cc: stable@vger.kernel.org Signed-off-by: Imre Deak imre.deak@intel.com --- drivers/gpu/drm/i915/display/intel_dp.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 21297bc4cc00d..208a953b04a2f 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -4538,6 +4538,23 @@ intel_dp_mst_disconnect(struct intel_dp *intel_dp) static bool intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *esi) { + struct intel_display *display = to_intel_display(intel_dp); + + /* + * Display WA for HSD #13013007775: mtl/arl/lnl + * Read the sink count and link service IRQ registers in separate + * transactions to prevent disconnecting the sink on a TBT link + * inadvertently. + */ + if (IS_DISPLAY_VER(display, 14, 20) && !display->platform.battlemage) { + if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT_ESI, esi, 3) != 3) + return false; + + /* DP_SINK_COUNT_ESI + 3 == DP_LINK_SERVICE_IRQ_VECTOR_ESI0 */ + return drm_dp_dpcd_readb(&intel_dp->aux, DP_LINK_SERVICE_IRQ_VECTOR_ESI0, + &esi[3]) == 1; + } + return drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT_ESI, esi, 4) == 4; }
On Mon, May 19, 2025 at 04:34:17PM +0300, Imre Deak wrote:
Due to a problem in the iTBT DP-in adapter's firmware the sink on a TBT link may get disconnected inadvertently if the SINK_COUNT_ESI and the DP_LINK_SERVICE_IRQ_VECTOR_ESI0 registers are read in a single AUX transaction. Work around the issue by reading these registers in separate transactions.
The issue affects MTL+ platforms and will be fixed in the DP-in adapter firmware, however releasing that firmware fix may take some time and is not guaranteed to be available for all systems. Based on this apply the workaround on affected platforms.
See HSD #13013007775.
v2: Cc'ing Mika Westerberg.
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13760 Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14147 Cc: Mika Westerberg mika.westerberg@linux.intel.com
Reviewed-by: Mika Westerberg mika.westerberg@linux.intel.com
On Mon, 19 May 2025, Imre Deak imre.deak@intel.com wrote:
Due to a problem in the iTBT DP-in adapter's firmware the sink on a TBT link may get disconnected inadvertently if the SINK_COUNT_ESI and the DP_LINK_SERVICE_IRQ_VECTOR_ESI0 registers are read in a single AUX transaction. Work around the issue by reading these registers in separate transactions.
The issue affects MTL+ platforms and will be fixed in the DP-in adapter firmware, however releasing that firmware fix may take some time and is not guaranteed to be available for all systems. Based on this apply the workaround on affected platforms.
See HSD #13013007775.
v2: Cc'ing Mika Westerberg.
In general, please don't resend just for the sake of adding a Cc. It triggers a full CI rerun.
BR, Jani.
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13760 Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14147 Cc: Mika Westerberg mika.westerberg@linux.intel.com Cc: stable@vger.kernel.org Signed-off-by: Imre Deak imre.deak@intel.com
drivers/gpu/drm/i915/display/intel_dp.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 21297bc4cc00d..208a953b04a2f 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -4538,6 +4538,23 @@ intel_dp_mst_disconnect(struct intel_dp *intel_dp) static bool intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *esi) {
- struct intel_display *display = to_intel_display(intel_dp);
- /*
* Display WA for HSD #13013007775: mtl/arl/lnl* Read the sink count and link service IRQ registers in separate* transactions to prevent disconnecting the sink on a TBT link* inadvertently.*/- if (IS_DISPLAY_VER(display, 14, 20) && !display->platform.battlemage) {
if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT_ESI, esi, 3) != 3)return false;/* DP_SINK_COUNT_ESI + 3 == DP_LINK_SERVICE_IRQ_VECTOR_ESI0 */return drm_dp_dpcd_readb(&intel_dp->aux, DP_LINK_SERVICE_IRQ_VECTOR_ESI0,&esi[3]) == 1;- }
- return drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT_ESI, esi, 4) == 4;
}
On Mon, May 19, 2025 at 04:53:08PM +0300, Jani Nikula wrote:
On Mon, 19 May 2025, Imre Deak imre.deak@intel.com wrote:
Due to a problem in the iTBT DP-in adapter's firmware the sink on a TBT link may get disconnected inadvertently if the SINK_COUNT_ESI and the DP_LINK_SERVICE_IRQ_VECTOR_ESI0 registers are read in a single AUX transaction. Work around the issue by reading these registers in separate transactions.
The issue affects MTL+ platforms and will be fixed in the DP-in adapter firmware, however releasing that firmware fix may take some time and is not guaranteed to be available for all systems. Based on this apply the workaround on affected platforms.
See HSD #13013007775.
v2: Cc'ing Mika Westerberg.
In general, please don't resend just for the sake of adding a Cc. It triggers a full CI rerun.
In this case I wanted that as well.
BR, Jani.
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13760 Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14147 Cc: Mika Westerberg mika.westerberg@linux.intel.com Cc: stable@vger.kernel.org Signed-off-by: Imre Deak imre.deak@intel.com
drivers/gpu/drm/i915/display/intel_dp.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 21297bc4cc00d..208a953b04a2f 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -4538,6 +4538,23 @@ intel_dp_mst_disconnect(struct intel_dp *intel_dp) static bool intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *esi) {
- struct intel_display *display = to_intel_display(intel_dp);
- /*
* Display WA for HSD #13013007775: mtl/arl/lnl* Read the sink count and link service IRQ registers in separate* transactions to prevent disconnecting the sink on a TBT link* inadvertently.*/- if (IS_DISPLAY_VER(display, 14, 20) && !display->platform.battlemage) {
if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT_ESI, esi, 3) != 3)return false;/* DP_SINK_COUNT_ESI + 3 == DP_LINK_SERVICE_IRQ_VECTOR_ESI0 */return drm_dp_dpcd_readb(&intel_dp->aux, DP_LINK_SERVICE_IRQ_VECTOR_ESI0,&esi[3]) == 1;- }
- return drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT_ESI, esi, 4) == 4;
}
-- Jani Nikula, Intel
linux-stable-mirror@lists.linaro.org
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Imre Deak -
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Mika Westerberg